Emmett was the second 2-year-old boy to go missing from Yavapai County in 10 days.

His case is believed to be unrelated to the disappearance of Sylar Newton -- another 2-year-old who went missing July 25 from a camping site in Rimrock and is presumed dead, D'Evelyn said Tuesday.

Emmett was reported missing by his mother at 8 p.m. Monday, the sheriff's office said in a news release.

The mother told authorities that she and her four children were at their home in the Dewey-Humboldt area, about 80 miles north of Phoenix. When the mother awoke from a nap Monday evening, Emmett -- last seen wearing a pajama top, diaper and no shoes -- was missing.

The family dog had also apparently wandered off with Emmett, but returned when called. The mother told police she searched around the home and immediate area without success.

Newnum said the door to the house was unlocked at the time of Emmett's disappearance, and it appears the boy walked as many four miles, crossing hilly, rough terrain, before he was found.

Newnum credited the muddy terrain in the area with helping find Emmett. He said the small footprints around the site indicate the boy "was by himself."